924Board.org

[bruni]

I just think you should be more objective, you are quoting an article published 8 years ago by someone selling the product he is writing about. he quotes his own tests which at best are vague and inconclusive. The key data which he makes no mention of is the air inlet temperature as it enters the cylinder head. In any event without independent testing his results are meaningless. When I see Phenolic spacers on a world rally car I will be converted
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1982 931
1975 harley sportster

[ideola]

[tuurbo]

Bruni I agree. I've just taken a peek through a few avenues of my own and I'm unimpressed with the quality and the quantity of evidence supporting the claim. But I don't really know the engineering literature.

Just like the electric supercharger, the phenolic spacers are in a price range that permits a bit of 'faith', if you will. The electric supercharger and the phonelic spacers differ, I think, in that the former isn't feasible on the face of it, with humble HP gains. Plus they make a horrible noise. But phenolic spacers are using materials that we do have reason to think will slow or retard heat transfer.

I see phenolic spacers as being worth the bet of $150 to try it out. Here's why.

At the time water injection was used in WWII aircraft, there was little if any information available to the general public on the validity of the claims of water injection. Further, it wouldn't be until 1993 or 1994 before the internet became available to everyone. Yet in the early 1980's, water methanol injection was being used in Formula One by Renault, Ferrari, even (I think later) Cosworth, and was later banned by F1. It was even used for similar purposes by Boeing. Yet there was nary a write up in local libraries at the time outlining the virtues of it, or studying it seriously. So had you searched you would have come up empty.

Bruni I like your example of air not having contact with the walls of the intake for very long. I think I get what you mean. But it is an empirical question. It is 'also' possible, I should think, that the intake manifold can act like an oven, and radiate heat into the center of the intake air stream, heating it up without direct contact with the walls in, perhaps, a short amount of time. I don't know enough about the theory to model it in my head.

I think at this stage it could be premature to say that the absence of a satisfactory and arbitrary empirical testing of phenolic spacers proves they cannot work. Or that it is a sham. It only proves that such tests are not available.

Dan those graphs are interesting. I would have liked to see IATs and a richer context description for the study, including a chart comparing:

Cars equipped with phenolic spacers
Cars equipped with non-phenolic spacers of equal length
Cars equipped without spacers.

The manufacturers are guilty of omitting temperature data, which is absolutely vital to the essence of the claim: That phenolic spacers reduce air charge temperature. On the face of it, these data don't support that claim.

The data kinda support another claim, that phenolic spacers add horsepower. But with unknown effect on intake air temperature.

How does the engine typically behave when you add runner length? And I wish I could make an informed guess about the utility of an extra cm of thickness. Not enough data here to make that inference.
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1980 924 turbo, MSD, Meth. Inj, otherwise stock.

[Scorpio]

[ideola]

tuurbo, you bring up some interesting points. Definitely, fluid dynamics comes into play here, and it is beyond my grasp to be able to predict how laminar flow vs. inducted heat vs. conducted heat vs. radiated heat would affect the charge air. I agree that objective data are scarce, at least so far (might be partly google's woeful search results!).

First, I'd like to point out that the Autospeed article actually did plot temps, and so it's worth repeating the IAT testing methodology:

[gegge]

I´m in for 1 set of spacers. If you find a set of studs, I´m interested in those as well. Please PM your payment instructions.
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Carl Fredrik Torkildsen

924 turbo -81 Carrera GT RESTOMOD
924 turbo -80 Dolomite De Luxe
924 -85 DP kit, BBS RS, M030 and tuned engine
924s -86 Black on black turbo with Fuchs

[bass gt]

Dan,

There is a very simple way to validate the possible effectiveness of these spacers.
Step 1. Before starting your car from cold, measure the temp of the intake runner by means of an infra red thermometer or such like.
Step 2. Take the car for a good run, and oncew the car is fully warmed up for a good 10-15mins, stop and repeat the measurement. I'll bet it's a fair bit hotter.
The way tolook at this is much like and intercooler. The cooler the mteal, the cooler the charge air, the better for power. Aluminium is a fantastic conductor of heat, and the head is just about the hottest item on the car. If you can stop the heat conducting into the charge pipes/runners, you can only gain.

Steve
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Front Wheel Drive is the Devil's work.

[ideola]

Steve,
I agree, and that's exactly how I'm going to measure once we get the spacers in.

I'm assuming you are OK with a universal single piece design? Or should we do individual smaller gaskets as in the 931 setup? So far, I think everyone that's posted is interested in a 931 application. Aside from the slotted stud hole, is there any reason you can think of that a single piece gasket would not work on a turbo head? Of course, you'd have to run NA gaskets with it...

Let me know.

Also, regarding thickness, would you prefer 6mm or 10mm thickness? Since these can be stacked, my thought was to go with 6mm (approx. 1/4"), which seems to be fairly standard in other applications...but for guys that aren't constrained by otherwise stock setups, add'l spacers could be stacked for more insulation. Thoughts?

I'm sending a turbo and NA gasket set in today, so if you guys could all chime in with your thoughts on these points, it will be helpful so I can give the manufacturer some guidance on what we want to do.
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erstwhile owner of just about every 924 variant ever made

[ideola]

[morghen]

IMO much of the effect of these spacers drops if you already have a good intercooler. If i drive my car on an open road the intake is REALLY cold. However in the city...they might help a bit.
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https://www.the924.com

[tuurbo]

[Rasta Monsta]

One question, wouldn't a 931 style (separate) spacers be cheaper, as in less material? I appreciate the desire to make them universal for bulkordercompulsionosis purposes, but is the unit really best for the 931?
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Toofah King Bad

• WeiBe (1987 924S 2.5t) - 931 S3

[ideola]

Yes, the individual style for a 931 would probably require less material. However, bear in mind that there are some guys here running turbos on NA heads and intakes, and there are also some guys running superchargers on NA heads. It seems like a universal design would be best so we don't have to come up with two different designs, part numbers, quantities, etc.

Also, according to some of the articles, there is also a benefit on normally aspirated cars but don't know that it would apply to the 924 given the known limitations of the NA head/intake. I am primarily trying to think ahead for the benefit of guys running superchargers and aftermarket turbos.
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erstwhile owner of just about every 924 variant ever made

[bruni]

Oh where do I start, Interesting that you quote data from a company called "Nissan Works" as from January 1997 until January 1999 I was technical manager for Nissan Motorsport Europe F2 rally team. during this time we won the British Rally Championship with the F2 Sunny. During this time Nissan also won the British Touring Car Championship with The Almera using a version of the same SR20 2L normally aspirated engine. Although the Race cars where run from the same workshop I had no involvement with that program although I was kept informed of all developments. I was responsible for all development on the Rally cars, engine, transmission and chassis. The race and rally engines where developed by two different companies independently of each other. The rally engine at best developed 285hp at 9250rpm the engine was capable of producing more, however the regulations meant that we had to keep the standard valve gear which restricted the maximum revs to about 9300. The regulations did however allow freedom in the design of the inlet system from the face of the cylinder head. I would of been quite happy to pay tens of thousands of £ to gain 5hp. Air inlet temperature is always a key factor in race engine development we found that the positioning, direction and timing of the fuel ejectors was the critical factor in reducing AIT (water injection was not allowed)
The original article does mention temperatures but they are manifold temperatures not AIT temperatures big difference, this is the critical measurement that you need and the one that all the companies leave out.

Thats all for now but I'll be back with more



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1982 931
1975 harley sportster

[ideola]